Robustness of the Vesuvian roofs under the combined overload and high temperatures due to air fall

During an explosive eruption, a construction is hit by several actions, always associated to elevated temperatures, causing fires, possible explosions and reduction of the mechanical properties of the structural materials. In this paper the attention is focused on the analysis of a specific volcanic event, the so-called air fall deposits, generally falling from the eruptive column due to gravity. The study, starting within the European COST Action C26 project "Urban habitat construction under catastrophic events" (2006-2010), is concerned with the Vesuvius area at Naples in Italy. It faces two important aspects. The first items the proposal of a model for the air fall deposits action on the basis of a similitude with the snow load. The second item is the robustness evaluation against the air fall deposits of the most common roof types in the Vesuvian area, which are made of timber, steel and reinforced concrete. Therefore, some protection systems for mitigating the effects of the combination of overloading and high temperatures on the examined roofing structures are identified.